Commit 071efd4

@@ -28,12 +28,7 @@ namespace domain
 
     public IEnumerable<Month> MonthsOverAvailableCapacity()
     {
-      return MonthsOverAvailableCapacity(Month.Now());
-    }
-
-    public IEnumerable<Month> MonthsOverAvailableCapacity(Month month)
-    {
-      return MonthsOverAvailableCapacity(Month.Now().UpTo(month));
+      return MonthsOverAvailableCapacity(Month.Now().UpTo(new Month(2099, 12)));
     }
 
     public IEnumerable<Month> MonthsOverAvailableCapacity(IRange<Month> months)
@@ -41,14 +36,21 @@ namespace domain
       var results = new List<Month>();
       months.Accept(month =>
       {
-        var production = TotalProductionFor(month);
-        Console.Out.WriteLine(production);
-        if( capacity.For(month).IsGreaterThan(production) ){
+        if(IsOverCapacity(month)){
           results.Add(month);
         }
       });
       return results;
     }
+
+    bool IsOverCapacity(Month month)
+    {
+        var production = TotalProductionFor(month);
+        if( capacity.AvailableFor(month).IsGreaterThan(production) ){
+          return true;
+        }
+        return false;
+    }
     IQuantity TotalProductionFor(Month month)
     {
       IQuantity result = new Quantity(0, new BOED());
@@ -79,9 +81,13 @@ namespace domain
       this.increases.Add(new Increase(quantity, month));
     }
 
-    public IQuantity For(Month month)
+    public IQuantity AvailableFor(Month month)
     {
-      //return this.increases.Single(x => x.IsFor(month)).;
+      return new Quantity(0, new BOED());
+      //return this
+        //.increases
+        //.Where(x => x.IsBeforeOrOn(month))
+        //.Sum(x => x.IncreasedCapacity());
       return null;
     }
 
@@ -96,10 +102,26 @@ namespace domain
         this.month = month;
       }
 
-      public bool IsFor(Month other)
+      public bool IsBeforeOrOn(Month other)
       {
-        return month.Equals(other);
+        return month.IsBefore(other) || month.Equals(other);
       }
+
+      public IQuantity IncreasedCapacity()
+      {
+        return this.quantity;
+      }
+    }
+  }
+  public static class Summation
+  {
+    static public IQuantity Sum(this IEnumerable<IQuantity> items)
+    {
+      var result = 0m.BOED();
+      foreach (var item in items) {
+        result = result.Plus(item);
+      }
+      return result;
     }
   }
 }

@@ -4,25 +4,23 @@ namespace domain
 
   public class Month : IComparable<Month>, IIncrementable<Month>
   {
-    int year;
-    int month;
+    DateTime date;
 
     public Month(int year, int month)
     {
-      this.year = year;
-      this.month = month;
+      date = new DateTime(year, month, 01);
     }
 
     public Month Plus(int months)
     {
-      var newMonth = ToDateTime().AddMonths(months);
-      return ToMonth(newMonth);
+      return ToMonth(date.AddMonths(months));
     }
 
-    DateTime ToDateTime()
+    public bool IsBefore(Month other)
     {
-      return new DateTime(year, month, 01);
+      return this.CompareTo(other) < 0;
     }
+
     Month ToMonth(DateTime date)
     {
       return new Month(date.Year, date.Month);
@@ -36,7 +34,7 @@ namespace domain
 
     public int CompareTo(Month other)
     {
-      return new DateTime(year, month, 01).CompareTo(new DateTime(other.year, other.month, 01));
+      return this.date.CompareTo(other.date);
     }
 
     public Month Next()
@@ -48,7 +46,7 @@ namespace domain
     {
       if (ReferenceEquals(null, other)) return false;
       if (ReferenceEquals(this, other)) return true;
-      return other.year == year && other.month == month;
+      return other.date == date;
     }
 
     public override bool Equals(object obj)
@@ -63,13 +61,13 @@ namespace domain
     {
       unchecked
       {
-        return (year*397) ^ month;
+        return (date.Year*397) ^ date.Month;
       }
     }
 
     public override string ToString()
     {
-      return string.Format("{0} {1}", year, month);
+      return string.Format("{0} {1}", date.Year, date.Month);
     }
   }
 

@@ -23,6 +23,7 @@ namespace domain
 
     public IQuantity Plus(IQuantity other)
     {
+      if(null == other) return this;
       return new Quantity(Amount + other.ConvertTo(Units).Amount, Units);
     }
 

@@ -7,7 +7,9 @@ namespace test
     {
       sut = new MCF();
     };
+
     static MCF sut;
+
     public class when_converting_6_mcf_to_boed
     {
       It should_return_one_boed=()=>

@@ -20,5 +20,20 @@ namespace test
         new Month(2012, 04).CompareTo(new Month(2012, 04)).ShouldEqual(0);
       };
     }
+    public class when_checking_if_a_month_is_before_another
+    {
+      It should_return_true_when_it_is =()=>
+      {
+        new Month(2012, 02).IsBefore(new Month(2012, 03)).ShouldBeTrue();
+      };
+      It should_return_false_when_it_is_not=()=>
+      {
+        new Month(2012, 03).IsBefore(new Month(2012, 02)).ShouldBeFalse();
+      };
+      It should_return_false_when_it_is_the_same_month=()=>
+      {
+        new Month(2012, 02).IsBefore(new Month(2012, 02)).ShouldBeFalse();
+      };
+    }
   }
 }

@@ -50,12 +50,12 @@
     <Compile Include="GreetingSpecs.cs" />
     <Compile Include="BOEDSpecs.cs" />
     <Compile Include="CalculatorSpecs.cs" />
-    <Compile Include="GasPlantSpecs.cs" />
     <Compile Include="MCFSpecs.cs" />
     <Compile Include="Mock.cs" />
     <Compile Include="MonthSpecs.cs" />
     <Compile Include="ProductionScheduleSpecs.cs" />
     <Compile Include="RangeSpecs.cs" />
+    <Compile Include="GasPlantSpecs.cs" />
   </ItemGroup>
   <ItemGroup>
     <None Include="packages.config" />